Watch Star Trek IV: The Voyage Home: The most acclaimed Star Trek adventure of all time with an important message. It is the 23rd century, and a mysterious alien probe is threatening Earth by evaporating the oceans and destroying the atmosphere. In their frantic attempt to save mankind, Admiral Kirk and his crew must time travel back to 1986 San Francisco where they find a world of punk, pizza and exact-change buses that are as alien to them as anything they have ever encountered in the far-off reaches of the galaxy. William Shatner and Leonard Nimoy return as Kirk and Spock, along with the entire Star Trek crew.